From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id A349A1F47C for ; Mon, 16 Jan 2023 19:51:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232856AbjAPTvQ (ORCPT ); Mon, 16 Jan 2023 14:51:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229712AbjAPTvN (ORCPT ); Mon, 16 Jan 2023 14:51:13 -0500 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 360272A994 for ; Mon, 16 Jan 2023 11:51:12 -0800 (PST) Received: (qmail 15991 invoked by uid 109); 16 Jan 2023 19:51:11 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Mon, 16 Jan 2023 19:51:11 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 652 invoked by uid 111); 16 Jan 2023 19:51:12 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Mon, 16 Jan 2023 14:51:12 -0500 Authentication-Results: peff.net; auth=none Date: Mon, 16 Jan 2023 14:51:10 -0500 From: Jeff King To: Junio C Hamano Cc: git@vger.kernel.org Subject: Re: [PATCH] format-patch: unleak "-v " Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Jan 16, 2023 at 10:35:53AM -0800, Junio C Hamano wrote: > > The word "unleak" in the subject made me think about UNLEAK(), so this > > is a small tangent. This is exactly the kind of case that I designed > > UNLEAK() for, because the solution really is "while you are assigning to > > X, also keep a copy of the pointer in Y to be freed later". > > Yup. I was originally planning to use UNLEAK(), but it felt ugly to > UNLEAK(rev.subject_prefix), as it stores borrowed pointer sometimes > and owned pointer some other times, which is the exact reason why I > started looking for a clean way to plug this leak. So I ended up > with declaring that the member should only store a borrowed pointer. That's actually one of the nice things about UNLEAK(). It is OK to over-mark something that may or may not be allocated. > The first sentence needs to be rephrased, as it does not make much > sense to have something usually be X and always be X at the same > time (I'd just remove "always" from there). Yep, agreed. -Peff